The silvery anthropomorphic robot cannot fulfill its assigned task to replace human astronauts on long and risky spacewalks, Dudorov said.

Fedor — short for Final Experimental Demonstration Object Research — was built to assist astronauts on the space station.

A storm of publicity surrounded Fedor’s space odyssey and provided some light relief for Russia’s beleaguered space industry, which in the last year has seen the unprecedented failure of a manned launch and continuing delays on construction of the Vostochny spacepad, where President Vladimir Putin upbraided officials last week.

But Fedor turned out to have a design that does not work well in space — standing 180 centimeters (5 feet 11 inches) tall, its long legs were not needed on spacewalks, Dudorov said.

The space agency said the legs were immobilized during the trip and Fedor was not programmed to grab hand rails to move about in microgravity.

Dudorov said developers were sketching out plans for a replacement “that must suit the demands of working on the outside of the ship.”

Fedor — officially Skybot F-850 — rocketed to the ISS on Aug. 22, entering the orbiting laboratory five days later.

On the station, the robot posed holding a Russian flag and for hugs with cosmonauts who were assigned to train it before touching down back on Earth on Monday.

A final tweet posted in an account in the robot’s name said: “Now I’m in my case. I await directions for further tests after the flight.”

Fedor was not the first robot to go into space. In 2011, NASA sent up Robonaut 2, a humanoid developed with General Motors that had a similar aim of working in high-risk environments.

It was returned to Earth in 2018 after experiencing technical problems.

In 2013, Japan sent up a small robot called Kirobo along with the ISS’s first Japanese space commander. Developed with Toyota, it was able to hold conversations in Japanese.